Math
posted by Square root on .
Is there a trick or formula or easy way to figure out square root mentally?

Memorize the common square roots
2 * 2 = 4
3 * 3 = 9
etc.
Then using those squares, you can estimate other square roots.
Example:
square root of 130 =
√ 121 = 11
√ 144 = 12
√ 130 is between 11 and 12 
Ok. Is there an easy way to figure the perfect square root for numbers 13 through 25.

3 * 3 = 9
4 * 4 = 16
5 * 5 = 25
Memorize the squares of 1  12 
So are u saying to memorize the squares for 13  25 as well? Not sure if my question is clear. For e.g. square of 23 is 529. By multiplying the last digit of 23 ( 3x3)= 9, same last digit of the number 529, is there a way I easily work out the first 2 numbers 52?

ahh, so you want to square the numbers , not take their square roots
A mental way to multiply any two 2digit numbers
e.g.
34 x 34
4x4 = 16 , so the last digit is 6 , with 1 to carry
3x4+ 4x3 = 24 plus the one to carry is 25
so the tens digit is 5 , with 2 to carry
3x3 = 9 with 2 to carry is 11
so 34^2 = 1156
the numbers don't have to be the same ...
e.g. 56 x 83
6x3 = 18 , so unit digit is 8 , carry 1
5x3 + 6x8 = 63 , so tens digit is 4 , carry 6
5x8 = 40, plus the carry 6 = 46
56x83 = 4648
but really, am I not just doing the steps of ordinary multiplication ??